curl/docs/libcurl/libcurl-easy.md
Daniel Stenberg eefcc1bda4
docs: introduce "curldown" for libcurl man page format
curldown is this new file format for libcurl man pages. It is markdown
inspired with differences:

- Each file has a set of leading headers with meta-data
- Supports a small subset of markdown
- Uses .md file extensions for editors/IDE/GitHub to treat them nicely
- Generates man pages very similar to the previous ones
- Generates man pages that still convert nicely to HTML on the website
- Detects and highlights mentions of curl symbols automatically (when
  their man page section is specified)

tools:

- cd2nroff: converts from curldown to nroff man page
- nroff2cd: convert an (old) nroff man page to curldown
- cdall: convert many nroff pages to curldown versions
- cd2cd: verifies and updates a curldown to latest curldown

This setup generates .3 versions of all the curldown versions at build time.

CI:

Since the documentation is now technically markdown in the eyes of many
things, the CI runs many more tests and checks on this documentation,
including proselint, link checkers and tests that make sure we capitalize the
first letter after a period...

Closes #12730
2024-01-23 00:29:02 +01:00

53 lines
1.9 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: libcurl
Section: 3
Source: libcurl
See-also:
- curl_easy_cleanup (3)
- curl_easy_init (3)
- curl_easy_setopt (3)
- libcurl (3)
- libcurl-errors (3)
- libcurl-multi (3)
---
# NAME
libcurl-easy - easy interface overview
# DESCRIPTION
When using libcurl's "easy" interface you init your session and get a handle
(often referred to as an "easy handle"), which you use as input to the easy
interface functions you use. Use curl_easy_init(3) to get the handle.
You continue by setting all the options you want in the upcoming transfer, the
most important among them is the URL itself (you cannot transfer anything
without a specified URL as you may have figured out yourself). You might want
to set some callbacks as well that are called from the library when data is
available etc. curl_easy_setopt(3) is used for all this.
CURLOPT_URL(3) is the only option you really must set, as otherwise
there can be no transfer. Another commonly used option is
CURLOPT_VERBOSE(3) that helps you see what libcurl is doing under the
hood, which is useful when debugging for example. The
curl_easy_setopt(3) man page has a full index of the almost 300
available options.
If you at any point would like to blank all previously set options for a
single easy handle, you can call curl_easy_reset(3) and you can also
make a clone of an easy handle (with all its set options) using
curl_easy_duphandle(3).
When all is setup, you tell libcurl to perform the transfer using
curl_easy_perform(3). It performs the entire transfer operation and does
not return until it is done (successfully or not).
After the transfer has been made, you can set new options and make another
transfer, or if you are done, cleanup the session by calling
curl_easy_cleanup(3). If you want persistent connections, you do not
cleanup immediately, but instead run ahead and perform other transfers using
the same easy handle.